Reversible percussion device for making holes in ground by compacting the latter

ABSTRACT

A reversible, pneumatically-operated percussion device having an axially-displacable air-control bushing positionable in one of two positions to correspondingly control forward and reverse movements of the device; the bushing cooperating with a casing and having projections interacting with those on the casing whereby reduction of operating pressure and a cooperating spring effect reversal of the impact effected by a percussor reciprocably supported in the housing of the device.

United States Patent Sudinishnikov et al.

[54] REVERSIBLE PERCUSSION DEVICE 1451 Dec. 12,1972

3,407,884 10/1968 Zygmunt et al. ..173/91 FOR MAKING HOLES IN GROUND BY 3,410,354 11/1968 Sudnishnikov et a]. ..173/135 COMPACTING THE LATTER 1 3,465,834 9/1969 Southworth, Jr. ..173/91 1 Inventors: Boris vasmevich sudinishnikav; 3,642,076 2/1972 Coyne ..173/ 135 Alexandr Dmitrievich Kostylev; P E J A L k Konstantin Stepandvich Gurkov; nmary xammer ames eppm Konstantin Konstantinovich Tu- Attomey Hlman Stem pitsyn; Vladimir Dmitrievich Plav- 51111111, 811 Of Novosibirsk, U.S.S.R. 1 ABSTRAT [73] Assignee: Institut Gornogo Dela Sibirskogo ot- A reversible, pneumatically-operated percussion d l i Ak d ii, N k, U,S S,R, device having an axially-displacabile air-control bush- [22] Filed: April 5 1971 ing positionable in one of two positions to correspondmgly control forward and reverse movements PP 131,136 of the device; the bushing cooperating with a casing and having projections interacting with those on the 52 US. Cl. ..173/91, 173/137, 175/19 casing whereby reduction of Operating Pressure and a [51] Int. Cl ..E21b 1/00, E2lb 11/02 cooperating spring effect reversal of the impact ef- [5 8] Field of Search ..l73/9l, 135, 137; 175/19 fected by a percussor reciprocably supported in the housing of the device. [56] References Cited 4 Claims, 2 Drawing Flgures UNITED STATES PATENTS 3,137,483 6/1964 Zinkiewicz ..173/91 1 fl 1 1 1 1 m l /1/ /1 /1// 7/ I 1 77 7/ f 0 e 9" 7 REVERSIBLE PERCUSSION DEVICE FOR MAKING HOLES IN GROUND BY COMPACTING THE LATTER The present invention relates to pneumatic reversible percussion devices for making holes in the ground by way of compacting the latter.

Known are reversible percussion devices which have a housing pointed at its one side and accommodating a percussor, said percussor forming front and rear variable volume, working chambers.

Under the action of compressed air supplied into the chambers, the percussor reciprocates and delivers percussions upon the housing, thus making drives the latter move in the ground.

Compressed air is supplied into the chambers along an air-supplying, stepped bushing which interacts with the percutor in the course of movement of the latter and is fixed in the rear portion of the housing by means of a nut so that it can displace in the latter in the axial direction. I

The compressed air is delivered into the front chamber from the rear one through ports provided in the tail portion of the percussor.

In order to extract the device from a hole (in case it encounters an obstacle that it cannot penetrate, or when making closed holes), movement is reversed by rotating a hose connected to the air-supplying bushing and displacing the latter relative to the nut. This results in a change in the rate of supply of the compressed air into the chambers and, consequently, in a change in the direction of the percussions delivered by the percussor upon the housing of the device, whereby the device will start moving in the reverse direction, i.e. will be'driven from and leave the hole.

The use of such reversible percussion devices has shown, however, that during the forward movement of the device there may occur a spontaneous stoppage of the air-supplying bushing in the nut, which makes it more difficult and sometimes impossible to reverse the device by rotating the hose.

It is an object of the present invention to provide such a reversible percussion device whose movement will be reversed by changing the working pressure of the operating compressed air.

In accordance with the present invention this object is accomplished whereby an air-supplying bushing has two rows of chamfered projections provided on the outer surface of a step of a smaller diameter, and a casing mounted between said projections, is rigidly secured to the tail portion of a housing and, during the reversing of the device, movement alternately interacts at its butt ends having chamfered projections cooperating with the rows of the projections provided on the airsupplying bushing to cause the latter displace in an axial direction from one position into another.

It is expedient to use a spring acting between the casing and a step of a larger diameter an the air-supplying bushing to effect the axial displacement of the bushing upon discontinuation of the supply of the compressed air.

It is also expedient provide the interacting butt ends for a short period of time frorn'its source of compressed air, which insures reliable operation of the device and simplifies the reversing procedure.

Other objects and advantages of the present invention will become apparent from the following detailed preferably pointed in its front end portion and reciprocably accommodating a percussor 2 oriented. upon the inner surface of the housing 1 by means of two belts or annular lands 3 and 4.

The space defined by the inner surface of the housing 1 and the outer surface of the percutor 2 essentially forms a front variable volume working chamber 5.

Disposed inside the tail portion of the percussor 2 is an axial or bore space accommodating an enlarged step 7 of a greater diameter of an air-supplying or control bushing 7. The space confined by the walls of the percu ssor 2 and the bushing 7 from a rear variable-volume working chamber 6 of the device.

The walls of the percussor 2 are provided with ports 8 used to intercommunicate the chambers 5 and 6 during a work and/or return stroke.

Through a step of a smaller diameter 7" the bushing 7 is mounted for axial movement a casing or sleeve 9 so that the bushing can move in the axial direction, the casing 9 being rigidly fixed in the housing 1 by means of a butt or rear end flange 9.

The device includes a compression spring 10 normally thrusting between the enlarged step 7 of a greater diameter of the bushing 7 and the casing flange 9.

, Secured to an axial pipe connection 9" of the casing 9 is a hose 11 used to supply compressed air from a compressor, (not shown) and the fllange 9' of the casing 9 is provided with apertures 12 used to exhaust the air used.

Provided on the butt or rear ends of the casing 9 (FIG. 2) are chamfered projections 13, 14, 15 and cavities l6'limited from the side of their butt ends by screw surfaces.

Provided on the outer surface of the step 7" of a smaller diameter of the air-supplying bushing 7 are two rows of chamfered projections 17 and 18, which face or oppose each other and whose butt surfaces are essentially screw threads.

The device functions as follows:

During the forward movement of the device, when the compressed air is supplied from a compressor through the hose l1 and axial duct 19 in the bushing 7 into the rear working chamber 6, the percussor 2 moves to the left, i.e. in the direction of the front chamber 5 (to the position shown in FIG. 1), and delivers a percussion or impact upon the inner surface of the housing 1, as a result of which the housing 1 moves forward and penetrates into the ground.

The ports 8 communicating the front chamber 5 (through the intermediary of the chamber 6, duct 19 and hose 11) with a source of compressed air are opened at a predetermined distance from the extreme left position of the percussor 2.

Due to its jumping-away on reaction impact and the built-up of pressure of the air in the chamber 5, the percutor 2 starts moving in the reverse direction since its effective, working area at the side of the chamber 5 is .greater than the effective-working area at the opposite side of the chamber 6 which is constantly communicated with the source of the compressed air.

With the ports 8 overlapped or covered by the side surface 7 of the air-supplying bushing 7, the percutor 2, while overcoming the resistance of the air in the chamber 6, continues moving in the reverse or rear direction, this being accompanied by expansion of the air in the chamber 5. j

' At the end of the reverse stroke of the percutor 2, its ports 8, after passing-by the step 7' of a larger diameter of the bushing 7, communicates the chamber 5, through the apertures 12, with the atmosphere, as a result of which there takes place an exhaust of the used During the forward movement of the device, the airsupplying bushing 7 occupies the extreme left (in FIG.

1) position, and its projections 17 contact the projections 14 of the casing 9.

Then, the working cycle of the device operation is repeated.

The back-blow force (the reacting force) arising during the device operation and acting in the direction opposite to that of the useful movement of the device, is balanced by the forces of friction arising between the housing 1 and the ground.

When the device encounters an obstacle (boulders, remainders of a foundation, cavities, etc.); or upon the completion of making a closed hole, the movement of the device is reversed, as a result of which, after it is supplied with compressed air, the device comes out (back) of the ground surface in which the hole was has made.

To reverse the movement of the device, it is necessary to disconnect it for a short period of time from the source of compressed air.

After the force of the pressure of the air in the chamber 6 becomes smaller than the compression force of the spring as a result of the air flow out into the atmosphere through clearances, the bushing 7 under the action of the spring moves to the left or forward. Thereby, the projections 17 of the bushing 7 are moved away from the fixed casing 9, and the projections 18 come in contact with the projections of the casing 9 with their screw surfaces. As a result of this, the bushing 7 during its further movement to the left or forward, under the action of the spring 10 will rotate about its longitudinal axis in the direction of arrow A (FIG. 2).

When compressed air is supplied into the chamber 6, the bushing 7 on compressing the spring 10, will move to the right or rearwardly and the projections 17 will come in contact with the projections 13 of the casing 9.

During its further movement to the right along the contacting screw surfaces of the projections 13 and 17 the bushin 7 will rotate or turn about its lon itudinal axis m the rrection of arrow A, as a result of w 1ch the pro- 5 jections 17 of the bushing 7 will enter cavities l6 and the bushing 7 will occupy its extreme right position.

With the bushing 7 in this position, there takes place a lead in the compressed admitted into the forward chamber 5 (as compared to the conditions of the device during forward movement), and a delay in the used air exhaust therefrom. During its movement in the direction of the front wall of the housing 1, the percussor 2 is stopped by the compressed air of the chamber 5 without having delivered a impact or percussion.

Due to an increase in the initial volume of the front chamber 5, and the larger effective working area on member 2, and the delay in the exhaust of the air therefrom, the percussor 2 during its reverse movement reaches the flange 9" of the casing 9 and delivers a rearwardly directed percussion upon the latter, as a result of which the housing moves rearwardly.

The reacting force acting upon the housing 1 in the direction opposite to that of the useful movement is balanced by the forces of friction arising between the ground and the housing 1.

We claim:

1. A reversible percussion device comprising a housreciprocation in the space in the latter under the action of the compressed air supplied alternately into said chambers; a stepped air-supplying bushing mounted in said housing so that it can displace in the axial direction and interacts through a step of a larger diameter with said percussor in the course of movement; said bushing having two rows of chamfered projections provided on the outer surface of a smaller diameter; a casing mounted on the step of a smaller diameter of said airsupplying bushing between said rows of the projections and rigidly secured to said housing; said casing having chamfered projections provided at the butt ends thereof and interacting during the reversing of the device movement the respective rows of the projec tions provided on said bushing.

2. A reversible percussion device according to claim 1, including a spring normally reacting between said casing and the step of a larger diameter of said air-supplying bushing for effecting axial displacement of said bushing upon discontinuation of the supply of the compressed air into the chambers of the device.

3. A reversible percussion device according to claim 1, in which the interacting butt ends of the projections of said air-supplying bushing and said casing are formed as screw surfaces.

4. A reversible percussion device according to claim 2, in which the interacting butt ends of the projections 

1. A reversible percussion device comprising a housing including a Working end and an internal space; a percussor reciprocatably disposed in said space of the housing and forming therein opposed, variable-volume working chambers; means operating to cause said percussor to impart to said housing percussions during its reciprocation in the space in the latter under the action of the compressed air supplied alternately into said chambers; a stepped air-supplying bushing mounted in said housing so that it can displace in the axial direction and interacts through a step of a larger diameter with said percussor in the course of movement; said bushing having two rows of chamfered projections provided on the outer surface of a smaller diameter; a casing mounted on the step of a smaller diameter of said air-supplying bushing between said rows of the projections and rigidly secured to said housing; said casing having chamfered projections provided at the butt ends thereof and interacting during the reversing of the device movement the respective rows of the projections provided on said bushing.
 2. A reversible percussion device according to claim 1, including a spring normally reacting between said casing and the step of a larger diameter of said air-supplying bushing for effecting axial displacement of said bushing upon discontinuation of the supply of the compressed air into the chambers of the device.
 3. A reversible percussion device according to claim 1, in which the interacting butt ends of the projections of said air-supplying bushing and said casing are formed as screw surfaces.
 4. A reversible percussion device according to claim 2, in which the interacting butt ends of the projections of said air-supplying bushing and said casing are formed as screw surfaces. 